The present invention relates generally to firearms, but more particularly to systems and methods regarding firearm trigger assemblies.
Generally, consistency and accuracy are understandably important in the art of firearms, especially in the field of competitive marksmanship. Regarding firearm trigger assemblies, inconsistency and inaccuracy may be attributed to at least two factors: friction and foreign particulates.
In the art of firearms, trigger assemblies may generally be coarsely divided into two types: direct-pull and override. Each trigger assembly type includes a sear pin which is adapted to abut a firing pin in the associated firearm. However, the two types of trigger assemblies differ in the way that the sear pin maintains the firing pin in a retracted, pre-firing state. A direct-pull trigger assembly generally includes a sear pin that travels generally in a linear path, which is substantially perpendicular to and intersects the path of travel of the firing pin. The sear pin included in an override trigger assembly, on the other hand, is adapted to rotate away from the firing pin, where such rotation is caused by the force of the firing pin acting on the sear pin. The sear pin may be spring biased towards the firing pin, but when the trigger is pulled, the firing pin force is allowed to overcome the sear pin spring bias force, thus allowing the firing pin to contact the ammunition round placed in the firearm.
As previously mentioned, two factors can contribute to undesirable inaccuracy and inconsistency in firearm trigger assemblies: friction and foreign particulates. Friction is of particular concern in direct-pull trigger assembly configurations. When in a cocked or pre-firing state, the direct-pull sear pin is in direct mechanical, frictional contact with a rear portion of the firing pin. To withdraw the sear pin and allow the firing pin to discharge the ammunition, the surface of the sear pin must be drawn across the surface of the portion of the firing pin, while the portion of the firing pin is biased towards the sear pin by a significant amount of force largely perpendicular to the direction of travel of the sear pin. Such interface creates a point of high frictional contact between the sear pin and the portion of the firing pin. Repeated firing actions begin to wear down both the sear pin and the portion of the firing pin, thereby altering the performance of the trigger assembly over time.
Foreign particulates, such as oil, cleaning solutions, dust and dirt, can also affect accuracy and consistency. In an attempt to shield trigger assemblies from foreign particulates, prior after-market or replacement override trigger assembly designs were provided as closed design, or housed, triggers, some of which include small springs, screws and ball bearings in an effort to provide adequate functionality. The theory of such closed designs is believed to rest on the basis that the moving parts of the trigger assembly should be shielded from dust. However, it has been discovered that, contrary to the conventional wisdom that shielding moving parts from dust should improve functionality, the housing, or closed design, actually impedes functionality over time by allowing foreign particulates to accumulate therein. In turn, the closed design or housed trigger assemblies must be disassembled to be cleaned, such as by removing cover plates. Unfortunately, such disassembly creates the risk that the small springs, screws and ball bearings will be lost or damaged. Additionally, foreign particulates may extend what would otherwise be considered a normal lock time. A lock time is the amount of time that passes from the time the trigger mechanism is actuated until the time the firing pin strikes the primer of the ammunition round. Generally, the shorter the lock time, the better. Normal lock times for, e.g., a bolt action rifle such as the Mauser M98, range from about four to about seven milliseconds, with newer models ranging from 2.5 to about seven milliseconds.
Accordingly, the art of firearm trigger assemblies would be enhanced by systems and methods suited to overcome at least the two mentioned causes of inconsistency and inaccuracy, while maintaining or reducing lock time.